Question

what is the atomic mass of an element?
the mass of an element using amu units
the mass of an element that is found on the periodic table
all of these
the weighted average of all isotopes of an element

Explanation:

Atomic mass is the weighted average of all isotopes of an element, usually expressed in atomic mass units (amu). The values on the periodic table represent this weighted - average atomic mass.

Answer:

C. All of these